Tutorial

Initial Server Setup with Ubuntu 20.04

Updated on August 9, 2021
English
Initial Server Setup with Ubuntu 20.04
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Ubuntu 20.04

Introduction

When you first create a new Ubuntu 20.04 server, you should perform some important configuration steps as part of the initial setup. These steps will increase the security and usability of your server, and will give you a solid foundation for subsequent actions.

When you create a DigitalOcean Droplet, you can choose an Ubuntu version that will be added to your new Droplet automatically. Simplify your setup with our out-of-the-box solutions.

Step 1 — Logging in as root

To log into your server, you will need to know your server’s public IP address. You will also need the password or — if you installed an SSH key for authentication — the private key for the root user’s account. If you have not already logged into your server, you may want to follow our guide on how to Connect to Droplets with SSH, which covers this process in detail.

If you are not already connected to your server, log in now as the root user using the following command (substitute the highlighted portion of the command with your server’s public IP address):

  1. ssh root@your_server_ip

Accept the warning about host authenticity if it appears. If you are using password authentication, provide your root password to log in. If you are using an SSH key that is passphrase protected, you may be prompted to enter the passphrase the first time you use the key each session. If this is your first time logging into the server with a password, you may also be prompted to change the root password.

About root

The root user is the administrative user in a Linux environment that has very broad privileges. Because of the heightened privileges of the root account, you are discouraged from using it on a regular basis. This is because the root account is able to make very destructive changes, even by accident.

The next step is setting up a new user account with reduced privileges for day-to-day use. Later, we’ll show you how to temporarily gain increased privileges for the times when you need them.

Step 2 — Creating a New User

Once you are logged in as root, you’ll be able to add the new user account. In the future, we’ll log in with this new account instead of root.

This example creates a new user called sammy, but you should replace that with a username that you like:

  1. adduser sammy

You will be asked a few questions, starting with the account password.

Enter a strong password and, optionally, fill in any of the additional information if you would like. This is not required and you can just hit ENTER in any field you wish to skip.

Step 3 — Granting Administrative Privileges

Now we have a new user account with regular account privileges. However, we may sometimes need to do administrative tasks.

To avoid having to log out of our normal user and log back in as the root account, we can set up what is known as superuser or root privileges for our normal account. This will allow our normal user to run commands with administrative privileges by putting the word sudo before the command.

To add these privileges to our new user, we need to add the user to the sudo group. By default, on Ubuntu 20.04, users who are members of the sudo group are allowed to use the sudo command.

As root, run this command to add your new user to the sudo group (substitute the highlighted username with your new user):

  1. usermod -aG sudo sammy

Now, when logged in as your regular user, you can type sudo before commands to run them with superuser privileges.

Step 4 — Setting Up a Basic Firewall

Ubuntu 20.04 servers can use the UFW firewall to make sure only connections to certain services are allowed. We can set up a basic firewall using this application.

Note: If your servers are running on DigitalOcean, you can optionally use DigitalOcean Cloud Firewalls instead of the UFW firewall. We recommend using only one firewall at a time to avoid conflicting rules that may be difficult to debug.

Applications can register their profiles with UFW upon installation. These profiles allow UFW to manage these applications by name. OpenSSH, the service allowing us to connect to our server now, has a profile registered with UFW.

You can see this by typing:

  1. ufw app list
Output
Available applications: OpenSSH

We need to make sure that the firewall allows SSH connections so that we can log back in next time. We can allow these connections by typing:

  1. ufw allow OpenSSH

Afterwards, we can enable the firewall by typing:

  1. ufw enable

Type y and press ENTER to proceed. You can see that SSH connections are still allowed by typing:

  1. ufw status
Output
Status: active To Action From -- ------ ---- OpenSSH ALLOW Anywhere OpenSSH (v6) ALLOW Anywhere (v6)

As the firewall is currently blocking all connections except for SSH, if you install and configure additional services, you will need to adjust the firewall settings to allow traffic in. You can learn some common UFW operations in our UFW Essentials guide.

Step 5 — Enabling External Access for Your Regular User

Now that we have a regular user for daily use, we need to make sure we can SSH into the account directly.

Note: Until verifying that you can log in and use sudo with your new user, we recommend staying logged in as root. This way, if you have problems, you can troubleshoot and make any necessary changes as root. If you are using a DigitalOcean Droplet and experience problems with your root SSH connection, you can regain access to Droplets using the Recovery Console.

The process for configuring SSH access for your new user depends on whether your server’s root account uses a password or SSH keys for authentication.

If the root Account Uses Password Authentication

If you logged in to your root account using a password, then password authentication is enabled for SSH. You can SSH to your new user account by opening up a new terminal session and using SSH with your new username:

  1. ssh sammy@your_server_ip

After entering your regular user’s password, you will be logged in. Remember, if you need to run a command with administrative privileges, type sudo before it like this:

  1. sudo command_to_run

You will be prompted for your regular user password when using sudo for the first time each session (and periodically afterwards).

To enhance your server’s security, we strongly recommend setting up SSH keys instead of using password authentication. Follow our guide on setting up SSH keys on Ubuntu 20.04 to learn how to configure key-based authentication.

If the root Account Uses SSH Key Authentication

If you logged in to your root account using SSH keys, then password authentication is disabled for SSH. You will need to add a copy of your local public key to the new user’s ~/.ssh/authorized_keys file to log in successfully.

Since your public key is already in the root account’s ~/.ssh/authorized_keys file on the server, we can copy that file and directory structure to our new user account in our existing session.

The simplest way to copy the files with the correct ownership and permissions is with the rsync command. This will copy the root user’s .ssh directory, preserve the permissions, and modify the file owners, all in a single command. Make sure to change the highlighted portions of the command below to match your regular user’s name:

Note: The rsync command treats sources and destinations that end with a trailing slash differently than those without a trailing slash. When using rsync below, be sure that the source directory (~/.ssh) does not include a trailing slash (check to make sure you are not using ~/.ssh/).

If you accidentally add a trailing slash to the command, rsync will copy the contents of the root account’s ~/.ssh directory to the sudo user’s home directory instead of copying the entire ~/.ssh directory structure. The files will be in the wrong location and SSH will not be able to find and use them.

  1. rsync --archive --chown=sammy:sammy ~/.ssh /home/sammy

Now, open up a new terminal session on your local machine, and use SSH with your new username:

  1. ssh sammy@your_server_ip

You should be logged in to the new user account without using a password. Remember, if you need to run a command with administrative privileges, type sudo before it like this:

  1. sudo command_to_run

You will be prompted for your regular user password when using sudo for the first time each session (and periodically afterwards).

Where To Go From Here?

At this point, you have a solid foundation for your server. You can install any of the software you need on your server now.

Get Ubuntu on a hosted virtual machine in seconds with DigitalOcean Droplets! Simple enough for any user, powerful enough for fast-growing applications or businesses.

Learn more here


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10 Comments


This textbox defaults to using Markdown to format your answer.

You can type !ref in this text area to quickly search our full set of tutorials, documentation & marketplace offerings and insert the link!

I have made a bash script to automate the setup process, hopefully this will be useful to someone else.

Bobby Iliev
Site Moderator
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October 19, 2020

Hello,

For anyone interested, I just created a similar video demo on how to do the initial server setup as described in this tutorial:

Hope that this helps!

Regards, Bobby

Much of the firewall was already preconfigured after deploying a Wordpress image from the DO marketplace, but the rest was golden. Thanks a lot!

The last command as root should be:

$ rsync --archive --chown=sammy:sammy /root/.ssh/ /home/sammy/.ssh/

Otherwise the authorized_keys file is created in the user’s home folder.

This website taught me how to enable my MacOS to SSH tunnel into my Linux terminal prompt without installing non-native apps or extensions. The instructions were clear and up to date. It took a long time to figure out.

The end note in Step #3 is misleading: “Now, when logged in as your regular user, you can type sudo before commands to run them with superuser privileges.”

For a first timer creating SSH keys this threw me off. I tried logging in as USER but obviously it didn’t work. It’s only later at step #5 where it’s explained how to copy the public key from ROOT to USER too.

Should change “NOW…” to LATER :)

Otherwise everything else worked fine thank you

If you faced with Permission denied (publickey), there few tips that help you in troubleshooting:

You may point directly to ssh key that you want use by -i parameter

ssh user_user@user_server_ip -i ~/.ssh/key_name.pub

For logs on client side use -v flag

ssh user_user@user_server_ip -v

Logs on server side

cat /var/log/auth.log

Possible troubleshooting for people having “Permission denied(publickey)” issues. Try this:

Check if you have .ssh folder in your root and new user folder:

  • a. enter “cd” (<- return to root folder)
  • b. enter “cd .ssh”

If not exist, then you’ve made some mistake adding publickey in your droplet. Try again re-creating your droplet.

  • c. enter “cd” (<- return to root folder)
  • d. enter “cd home/sammy” (<- use your user name here)
  • e. enter “cd .ssh”

If not exist, probably rsync command did not end well. Instead of:

“rsync --archive --chown=sammy:sammy ~/.ssh /home/sammy”

try substitute “–archive” with “-a”.

Then, repeat steps from “.c” to “.e” and check again if .ssh folder has been created.

If folder still not exist, try having a lecture here, it may help.

Resolve this first, then check again logging in with your new user.

If you’re still having issues:

  • a. go here
  • b. repeat the process following OpenSSH or PutTy steps but, instead of create another “root” user (people using PutTy: field “Auto-login username”), use the user name you create before (eg: “sammy”).

Save your new session and try open it.

Hope it helps.

THX Mr. Boucheron!

I tested it on a brand new droplet with Ubuntu 21.10, DO Bangalore data center.

jimmy@ubuntu-s-1vcpu-1gb-blr1-01:~$ cat /etc/os-release
PRETTY_NAME="Ubuntu 21.10"
NAME="Ubuntu"
VERSION_ID="21.10"
VERSION="21.10 (Impish Indri)"
VERSION_CODENAME=impish
ID=ubuntu
ID_LIKE=debian
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
UBUNTU_CODENAME=impish
jimmy@ubuntu-s-1vcpu-1gb-blr1-01:~$

All is perfect.

I’m setting up a Ubuntu machine as per your tutorial

You are suggesting that the out of the box root account should be disabled and a new user with sudo access be created.

When installing applications (node, mongo, nginx etc) should these apps be installed using the new account ? And in which context should these apps run ?

Could you please explain a bit more on this.

Thanks

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